Speciation of iron using HPLC with electrochemical and flame-AAS detection

Summary A combined detection system for HPLC is presented, which consists of an electrochemical detector for iron(II) detection and an on-line flame-AAS detector for total iron. Detection limits are 5 ng iron for AAS and 1 ng iron(II) for electrochemical detection. Quantitative analysis of separated iron species is possible, even if iron(II) and iron(III) coelute. The proposed system is used for the investigation of coupled complexation and redox equilibria (e.g. Fe + oxalate). The application to fruit juice and wine is also presented. The predominant species found in apple juice are iron(II)-malate and iron(III)-citrate and in white wine iron(II)- and iron (III)-tartrates.